/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/GroupTopology.h
These are helper methods to get out a value when you know you only have one, or you don't care which one of the existing ones you grab. They only exist becauseTSetdoesn't have a clean way to grab one arbitrary element besides *TSet::TConstIterator(MySet). The hope is that these are slightly cleaner.
int32 GetASelectedGroupID() const